Wireless Charging Shift Ahead

At least four different approaches to wireless charging are vying to power billions of next-generation mobile devices. Today only one has a beachhead in about a million systems: the Wireless Power Consortium's Qi inductive charging technology.

By 2018, analysts say, the race will be all but over with one player dominating the 700 million systems using wireless charging. Experts expect a technology shift to resonant charging after a generation of hybrid inductive/resonant products currently coming on the market. Before it's over, Apple is expected to debut what could be a wild-card proprietary approach.

Wireless charging "standards have to converge, and I think this year they will figure out this market is not taking off until they get together," Henry Samueli, the chairman and CTO of Broadcom, said at a company event in December in San Francisco. "It's about much more than a smartphone market. The main driver is the Internet of Things."

Ryan Sanderson, a wireless charging analyst at IHS, told us the mobile phone and tablet markets will be key to volume adoption of wireless charging in the coming years. IHS forecasts assume that at least one major cellphone manufacturer will integrate wireless power capability throughout its ecosystem by 2016.

"Apple is probably not eager to adopt another standard for it. They'll want to develop their own thing. They have a huge influence, along with Samsung," IHS analyst Jason dePreaux told us. "It will take those two companies to create a standard, not just saying the standard or joining an alliance, but actually building it in. It's several years away, though, especially on the Apple side."

Three types of main wireless charging technologies are contenders in the race to mainstream use -- magnetic induction, magnetic resonance, and niche solutions such as radio frequency. On the following pages, we will explore each in some detail. Though dePreaux said there isn't much difference in power or charging time among the technologies, an Ars Technica speed test of the Qi (pronounced chee) technology showed that charging a Google Nexus 7 wirelessly took nearly three times as long as using a power adapter.

Trade groups of chip makers and patent holders back different charging platforms. The Wireless Power Consortium (WPC) backs inductive and bridge solutions, while the Association for Wireless Power (A4WP) champions resonance. Seeing the writing on the wall, the Power Matters Alliance has moved to embrace resonant charging, as well.

The startup Humavox is going it alone with an approach that is based on what it calls radio frequency charging. Still, market watchers say other players and technologies could emerge before the dust clears.

"In the future, it's possible that technologies which offer the consumer even more freedom of space and distance to charge wirelessly -- RF perhaps being an example of this -- will enter the market and compete with resonant technologies," Sanderson said. Advancements are likely several years out. "In my opinion, it will be difficult for a new technology to enter the market once an infrastructure is in place, and therefore, if one technology is adopted in volume in the next two years, it is likely to remain the technology of choice for the future."

Last year, 20 million wireless charging receivers were shipped, and though most of them were inductive, Sanderson expects the market to grow to 700 million devices in four years. Inductive and resonant wireless chargers will ship in 2014, with resonant/bridge solutions expected to ramp up in the second half of the year.

A standard is "not taking up faster because folks are confused by the existence of what appears to be competing standards," John Perzow, the WPC's vice president of market development for Wireless Power Consortium, told us. "The well-known standards -- Power Matters Alliance, A4Wp, WPC -- those differentiating is making it hard for groups to combine… They don't share communication protocol. They won't talk to each other."

But consolidation is necessary before the technology can become ubiquitous. Only inductive and radio frequency products are available to the public, with Qi inductive technology built into products such as the Samsung Galaxy S4, Nokia Lumia 920, and Google Nexus phones and tablets. Major market players such as Broadcom, HTC, and Samsung are among the members of both industry groups.

Yes, but this does add any improvement in life, it removes the wires clutter the only way you can think it is beneficial, but Docks are already doing that. Also this requires 2A charger, where as docks will require only 1A charger, virtually doubles the power consumption.

Based on my usage, it does two important things, it holds my phone in place and charges it without fooling around with cables when I get in my car.

Evidently it can hold up a Nexus 7 too because it uses magnets as well as a sticky surface.

It's Qi based which is fine since I'm going to use it with a Nexus 4 and Nexus 5 when I upgrade.

What does not make much sense to me are desktop pad type chargers. You're not really going to use your device while it is on the pad and as "wireless" as these chargers are, they still have a power cord.

I don't expect that these chargers are ever going to realize Tesla's dream of wireless power transmission so I don't see where low efficiency long distance (a few inches) chargers are going to be game changers for consumer electronics, a standard like Qi should do just fine (if it can support enough power).

For medical devices I can see a good case for the RF stuff but that shouldn't influence the smart phone charger market.

Bottom line, I will be using a wireless charger but I'm not giving up my standardized usb cable because it is better for many situations.

The challenge is the efficiency of inductive charging technology drastically falls down over distance from the charger. From user's perspective the wireless charging would add value if there are no restrictions regarding how the phone could be placed on the charger. Another requirement I could think of is that the same charger to work with phones from different manufacturers...hence I think only one among these technologies would survive in long run...and some point of time there would be a need for making a standard for this (like USB charging). Finally I would not want to change the charging station as frequently as phones...hence the technology should be forward looking, which should last for several years.

Humavox RF talks of a range, but the main frequency mentioned is 2.4GHz-- they really should pick a different frequency than WiFi (device won't be connected to WiFi while charging? Really?) and microwave ovens (this isn't WiFi mW signal, but several thousand mW it sounds like. I am not sure I want several potential multiple watt "microwave oven" transmitters sitting on a table next to the bed, or facing me while working). Sure there are technical solutions for 2.4GHz, but the first kitten fried-- in reality or not-- by a failing Humavox 2.4GHz open top cup shaped nest "microwave oven" will severely dent their product reputation. On the up side, perhaps one could hard boil an egg in the nest while working those long hours...

I agree with two of the conclusions that Kinnar expressed, that there's really two markets and that the in-ear and at least some internet of things will go with RF.

As far as smartphones and tablets are concerned I would say the biggest issue is with the smartphones. Talk time, in heavy use scenarios, is way overoptimistic. Using speakerphone while browsing is very power consuming. Not only the display and the 4G but the cellular connection. In congested metropolitan areas the transmitter often has to up power to get through interference. These scenarios can drain a battery such that you can't make it through the day.

So, with the smartphone we're at the mercy of chargers during the day. The USB port, especially the 2.1A type do the job, however they are inconvenient when call is made or answered, usually disconnecting the USB connector to the phone. This is not only an inconvenience but a potential reliability problem with the phone connector.

I see charging stations becoming ubiquitous, just putting phone on a pad will be very attractive feature and certainly offices and homes can be easily equipped.

On the technical side I see a problem. In the article there is mention that the induction and resonant technologies presently have relatively low power delivery capabilities. New USB charging is specified at 2.1A, that's because the older 1A has proved inadequate. My Nokia Qi is specified to charge between 0.5 and 1.5A. Providing such technology as a feature on a car won't work. A major use for smartphones in cars is for GPS apps. The GPS apps, by default leave the display on. The current wireless charging will not even supply enough power to keep the phone from discharging.

I find it especially frustrating since the wonderful initiative to standardize charger connectors so that we don't need to fill up drawers with obsolete chargers is being thwarted by the emerging multiplicity of wireless charging devices.